A simple technique for studying struvite crystal growth in vitro

Summary Struvite urolithiasis forms as a consequence of a urinary tract infection by urease-producing species of bacteria such as Proteus mirabilis. Ammonia, produced by the enzymatic hydrolysis of urea, elevates urine pH causing a supersaturation and precipitation of Mg⁺⁺ as struvite (NH₄MgPO₄). Calcium often precipitates as well, forming the mineral carbonate-apatite (Ca₁₀(PO₄)₆CO₃). We have developed a procedure based on direct observation by light microscopy whereby struvite crystal growth can be quickly monitored in response to chemical changes in urine. As struvite crystals assume a characteristic shape or crystal habit based on their growth rate, the effect of urine chemistry and the action of various crystallization or urease inhibitors on struvite formation can be quickly shown. In addition preliminary effects of alkaline pH, or the presence of toxic compounds on bacteria can also be shown through their loss of motility.     

奇异变形杆菌蛋白质双向电泳条件的优化及评价

目的：优化针对奇异变形杆菌蛋白质组学研究的双向电泳(2-DE)条件及其相关技术体系,阐明样品处理过程中超声功率、振摇时间和上样量对2-DE图谱的影响。方法：选取1株奇异变形杆菌,分别采用超声功率为130 W和80 W超声法裂解菌体提取总蛋白,将2种方法提取的蛋白在同一条件下进行等电聚焦和聚丙烯酰胺凝胶电泳(SDS-PAGE);超声功率为80 W提取的奇异变形杆菌总蛋白,分别取上样量1和2 mg,在同一条件下17 cm胶条上进行双向电泳。结果：超声功率为130 W处理的样本得到的2-DE图谱中蛋白斑点较少,而超声功率为80W处理的样本蛋白点多、清晰且重复性好。上样量为2 mg得到的图谱中横纵条纹明显,蛋白斑点分离度较差,而上样量为1 mg时横纵条纹较少,蛋白斑点分离度较好。结论：采用低功率超声且较少上样量处理样品能得到较好的2-DE图谱。
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奇异变形杆菌周期性群集运动的研究

目的研究奇异变形杆菌(proteus mirabilis,PM)迁徙生长过程中形态、数量、呼吸酶活性等指标周期性变化.方法在培养基中加入2,3,5-三苯基四唑氯化物(2,3,5-tetraphenyltetrazolium chloride,TTC)作为呼吸酶活性的指示剂观察细菌呼吸酶活性的变化.采用透射电子显微镜对细菌形态、鞭毛进行对比观察.比浊法计数PM在时间、空间上的数量的变化.结果PM在固体培养基迁徙生长过程中出现菌体数量逐渐减少、形态由短小到细长、鞭毛由少变多、呼吸酶从有活性向无活性转变的周期性变化.结论PM在培养基迁徙生长过程中,微观上出现菌体长度、鞭毛数量、细菌密度等周期性变化,宏观上出现水波样的环状运动,这是环境、鞭毛、细胞间信号传递和细菌密度等多因素联合作用的结果.     

一起由奇异变形杆菌和伦敦沙门菌引起食物中毒的实验室检验

目的:对一起食物中毒的采集样本进行相关微生物学检验,确定引起食物中毒的病原菌。方法:根据流行病学调查及临床表现,选择疑似的病原菌,依据GB/T4789-2003、GB/T4789-2008、WS/T9-1996、《卫生防疫细菌检验》对采集的样品进行病原菌分离与鉴定。结果:从2份剩余食物鸭脖子、1份患者粪便及1份肛拭样中均检出奇异变形杆菌和伦敦沙门菌。结论:该次食物中毒为一起因奇异变形杆菌和伦敦沙门菌混合污染食物所致。     

奇异变形菌中整合子分布及耐药性分析

目的 了解院内奇异变形菌中各类整合子的携带分布情况、阳性菌株可变区基因盒类型以及其与宿主菌耐药表型的相关性,从而为临床治疗和院内感染控制提供参考。方法 采用PCR扩增和琼脂糖凝胶电泳等方法,将本院2016年1月—2018年12月份从临床标本中分离得到的150株奇异变形菌进行第1、2和3类整合子的筛选,并对整合子阳性菌株可变区进行测序分析以及宿主菌的耐药性进行相关性分析。结果 150株奇异变形菌中携带整合子的菌株共有91株,阳性率为60.7%,其中第1类整合子阳性菌株有30株,占20.0%;第2类整合子阳性菌株22株,占14.7%;同时携带第1和2类菌株39株,占26.0%;未筛出第3类整合子;在91株整合子阳性菌株中,86株可变区出现扩增产物条带,其余5株可变区未见扩增产物;第1类整合子阳性菌株可变区携带的耐药基因盒主要为AadA2、DfrA32,第2类整合子阳性菌株可变区携带耐药基因盒主要为DfrA1;可变区携带AadA2的菌株对庆大霉素和妥布霉素的耐药率显著高于整合子阴性菌株(P<0.01),可变区携带DfrA1或DfrA32的菌株对复方磺胺甲噁唑(即甲氧苄啶/磺胺甲噁唑)的耐药率也明显高于整合子阴性菌株(P<0.01);91株整合子阳性菌株对氨苄西林/舒巴坦、复方磺胺甲噁唑、环丙沙星、庆大霉素、头孢曲松、妥布霉素和左氧氟沙星的耐药率均显著高于整合子阴性菌株(P<0.01)。结论     

变形杆菌骨伤科感染及药敏分析

为了加深临床对变形杆菌感染的认识,了解该菌的药物敏感情况,采用回顾性方法,对１９９７年１月～１９９９年７月骨伤科感染标本中分离出的２０８株变形杆菌,结合该院常用的１５种抗生素药敏试验结果进行整理分析,结果显示变形杆菌的感染率占１２．４％。其中,开放性骨折占６５．４％,其次为骨髓炎,占２３．１％,两次为术后感染,占７．６％。诺氟沙星、环丙沙星、丁胺卡那霉素、妥布霉素及第３代头孢菌素是对变形杆菌敏感率     

Paradominant inheritance,a hypothesis explaining occasional familial occurrence of sporadic syndromes

Heterozygous individuals carrying a “paradominant” mutation, as a rule, are phenotypically normal. Therefore, the mutation can be transmitted unperceived through many generations. The trait becomes manifest when a somatic mutation occurs during embryogenesis giving rise to loss of heterozygosity and forming a mutant cell population, being either homozygous or hemizygous for the mutation. This concept explains the occasional familial occurrence of usually sporadic traits like the Klippel-Trenaunay syndrome and others. Am. J. Med. Genet. 85:359–360, 1999. © 1999 Wiley-Liss, Inc.     

Nouvelles perspectives nosologiques et thérapeutiques pour les malformations vasculaires syndromiques à composante veino-lymphatique

Vascular malformations are poorly recognized constitutional anomalies which arises during early childhood. Several classifications tried to draw a distinction across the different entities. Recent advances in molecular biology have contributed to the update of their nosology. Syndromic vascular malformations are an example: while Klippel-Trenaunay syndrome, Proteus or CLOVES syndrome share many common features, understanding of pathological mechanism and specially the role of the PIK3/AKT/mTOR pathway enables us to rethink their classification. Then, some syndromes associated with overgrowth and vascular malformation have been grouped under a single term: “PIK3CA-related overgrowth spectrum” (PROS), and this group continues to grow. This new approach suggests new treatment options. Rapamycin, a PIK3/AKT/mTOR pathway inhibitor, demonstrated its efficiency for some forms of PROS. Targeted therapies such as PIK3 or mTOR selective inhibitor are still in a developmental phase and results are encouraging. This is an example of personalized medicine with significant therapeutic benefit for some patients. However, genotype relation with therapeutic efficiency must be clarified and physicians should pay attention to possible negative effects of these drugs, especially for young patients.     

双重PCR检测沙门氏菌和变形杆菌方法的建立

目的:建立快速鉴定腹泻患者粪便标本中和变形杆菌的双重聚合酶链式反应（PCR）方法。方法:针对沙门氏菌属特异基因invA和变形杆菌属特异基因tuf分别设计特异性引物,2013年5月-10月天津某医院肠道门诊腹泻患者粪便标本经SS培养基分离培养后,对可疑菌株同时进行invA-tuf基因双重PCR鉴定和生化鉴定,比较两种方法结果的一致性;对沙门氏菌进一步行血清学分型。结果:双重PCR和生化反应都各自鉴定得到沙门氏菌31株和变形杆菌62株,而且二者鉴定结果完全一致;31株沙门氏菌包括鼠伤寒、肠炎等常见血清型和格兰扁、菲尔摩雷等罕见血清型,均能扩增出283 bp长度片段,62株变形杆菌包括48株奇异变形杆菌、8株普通变形杆菌、2株潘氏变形杆菌、4株产黏液变形杆菌,均能扩增出541bp长度片段。 结论:invA-tuf基因双重PCR方法能够快速可靠地鉴定SS培养基上生长的沙门氏菌和变形杆菌。      

Structures and serology of the O-antigens of Proteus strains classified into serogroup O17 and former serogroup O35

Introduction Bacteria of the genus Proteus are facultative pathogens which commonly cause urinary tract infections. Based on the serological specificity of the O-chain polysaccharide of the lipopolysaccharide (O-polysaccharide, O-antigen), strains of P. mirabilis and P. vulgaris have been classified into 60 serogroups. Studies on the chemical structure and serological specificity of the O-antigens aim at the elucidation of the molecular basis and improvement of the serological classification of these bacteria. Materials and Methods The O-polysaccharide was prepared by acetic acid degradation of the lipopolysaccharide isolated from dried bacterial mass of each strain by hot phenol/water extraction. ¹H- and ¹³C-NMR spectroscopy was used for structural studies. Serological studies were performed with rabbit O-antisera using enzyme immunosorbent assay, passive hemolysis test, and the inhibition of reactions in these assays as well DOC-PAGE and Western blot. Results Four Proteus strains belonging to serogroups O17 and O35 were found to possess similar O-polysaccharide structures, in particular having the same carbohydrate backbone built up of tetrasaccharide repeating units. However, they differ in the presence or absence of additional substituents, such as phosphoethanolamine in P. mirabilis O17 and glucose in P. penneri O17, as well as in the pattern and degree of O-acetylation of various monosaccharide residues. Serological studies also showed close relationships between the O-antigens studied. Conclusions Based on these data it is proposed to reclassify strain P. mirabilis PrK 61/57, formerly representing the O35 serogroup, into the serogroup O17 in the Kauffman-Perch classification system of Proteus.